E92 m3 whole Bank 1 instant misfire immediately after start

[Honda]

Broken valve springs are becoming a common issue on s65

[charliev68]

I think there are a lot of broken valve springs that people don’t know about. It can break but still function relatively normal until it coils over and locks the valve open.
One way to check is run a misfire monitor counter check thru the obd2 diagnostic. It will tally all the misfires that have not yet set off codes.
I don’t know if it’s a bad production batch of springs or because our engines like revs but the springs of the s65 are probably starting to fatigue. Might be a start of an ongoing problem.

[spammysammich]

It has sorta always been a low level occurrence issue with these cars. Do a deep search and you’ll see people reporting valve spring failure all the way back to 2009. But a wide spread issue? Not sure. You have to take into account confirmation bias of internet searching and forum bias. People that don’t know anything about internet forums or don’t care to participate aren’t going to chime in. Neither are people experiencing no problems, until they do. Usually the only active participants in forums are people looking for help.

[m3cole]

Seems like it will become more of an occurrence considering the age of the cars and miles will continue to go up. Super high revving engines would in theory have a good amount of valvetrain wear due to high engine speeds.